长跨距无中继光纤传输系统的实验与分析

无中继光纤传输系统是指在光纤链路上不包括任何光电中继设备的传输系统。结合2.5 Gbit/s、10 Gbit/s、40 Gbit/s三种典型信道速率下的长跨距无中继传输系统实验,分析了实现大容量长跨距无中继传输的物理受限因素,探讨了应对的关键性技术,并通过实验证明了双向泵浦喇曼放大技术在无中继光纤传输系统中潜在的重要应用价值。     

单通路2.5 Gbit/s系统超长距离传输技术

文章主要讨论了单通路2．5Gbit／s数字系统超长传输的实现技术。对于各种影响2．5Gbit／s系统超长传输的因素，如光缆衰耗、色散和非线性等，分别进行了详细的介绍，并针对这些限制提出了掺铒光纤放大器、色散补偿技术等常用的手段，结合目前最新的技术进展，从理论和实践上，着重对光纤喇曼放大器这种特殊的放大器技术做了分析。最后，提出了2．5Gbit／s单通道系统在250km光纤中无中继传输的应用案例。     

电力系统光纤通信超长站距传输技术的研究

讨论了超长站距传输系统的各种实现技术。深入分析了超长站距传输系统的OSNR受限问题,提出并介绍了解决方案,重点包括光纤喇曼放大器和遥泵放大器。最后提出了2.5 Gbit/sSDH系统单跨距350 km无中继传输方案。     

超长距光传输技术在宁夏电网中的应用

随着特高压交直流电网的不断建设,电力通信系统对超长站间距离、无中继站光传输技术的需求也日益凸显。针对超长距无中继传输技术在实际应用过程中面临的问题,从线路损耗、色散效应以及光信噪比三个关键因素进行分析,结合宁夏电网第一条省内超长距无中继传输系统即六盘山750 kV变电站至灵州±800 kV换流站通信系统的建设,通过运用光放大器、纠错、色散补偿、拉曼等关键技术,实现2.5 Gbit/s速率、10 Gbit/s速率长传系统通信。应用结果表明:超长距光传输技术的应用实现了六盘山750 kV变电站至灵州换流站间的超长站距通信,满足了系统运行的各项性能指标,节省了大量建设资金及维护费用。     

光纤拉曼放大器在云南电力通信网的运用

损耗、色散、非线性等是限制光信号长距离传输的主要问题,光纤拉曼放大器正是补偿损耗实现光长距离传输的有效方法。文章阐述了光纤拉曼放大器的原理及特点,提出了解决光纤长距离传输相应的技术对策。采用光纤拉曼放大器对传输光纤在损耗、色散、非线性及偏振模等方面进行优化,可以满足长距离、大容量传输系统的要求。分析了实际运用中的参数算法和相关指标要求,介绍了测试方法和结果,实现了光信号超长距离的传输。同时节约了工程建设投资,降低了通信运行维护费用,为光通信系统建设提供了参考。     

超长跨距传输实验取得创新成果

近日由国网信息通信有限公司牵头,武汉光迅公司和美国康宁公司组成的联合测试小组在超长跨距测试项目上取得突破性成果。在基于G.652光纤以2.5 Gbit/s速率传输的SDH系统上,单跨距最长传输距离达到了创纪录的514 km;     

光纤通信系统的超长距离传输方案

延长单段无中继光传输距离对于减少网络节点间的电中继和光中继，降低长距离传输成本具有很实际的意义。文章分析了光纤通信超长距离传输的关键技术，及其性能优势和经济效益，同时介绍了国内外超长距离光纤传输技术现状；提出了基于DRFA EDFA混合放大技术，实现传输速率为2．5Gbit／s、无中继距离为250km的传输技术解决方案。方案采用成熟的技术，使用了市场上比较常见的器件，具有很高的性价比。     

超长距离光纤传输在华北电网中的实验与应用

超长距离光纤传输一直是华北电网实际遇到且亟待解决的问题。随着技术的发展和成熟,华北电网结合具体工程,在2005年采用了喇曼光纤放大(Raman PA)技术,安排了2.5 Gbit/s、无中继传输距离为207 km的实验电路。该电路投运后运行良好,并经过了现场测试,为华北电网实现超长距离的光纤传输取得了实际经验和数据。文章给出了实验电路、测试数据和建议,为业内人士提供参考及讨论。     

DWDM波长转换技术在超长距SDH传输网中的应用

SDH光信号在超长中继距离传输中存在信噪比下降的问题.文章介绍了在500 kV东明开关站至三堡变光通信工程实施中,采用DWDM波长转换技术克服这一难题的成功经验.通过案例可以看出,在超长中继距离SDH光通信线路中,锁定SDH输出信号的中心频率并在接收端采用光过滤器对噪声进行抑制,是解决信噪比下降、保证传输质量的有效办法.     

DWDM波长转换技术在超长距SDH传输网中的应用

SDH光信号在超长中继距离传输中存在信噪比下降的问题。文章介绍了在500kV东明开关站至三堡变光通信工程实施中，采用DWDM波长转换技术克服这一难题的成功经验。通过案例可以看出，在超长中继距离SDH光通信线路中，锁定SDH输出信号的中心频率并在接收端采用光过滤器对噪声进行抑制，是解决信噪比下降、保证传输质量的有效办法。     

507km超长站距无中继光传输系统

文章介绍了采用远泵掺铒光纤功率放大技术、远泵掺铒光纤前置放大技术、拉曼噪声抑制技术和前向误码纠错等技术,工程上常用的G.652光纤所构成的速率为2.5 Gbit/s、站距为507 km的超长站距无中继光纤通信系统.     

Highly spectral-efficient optical code-division multiplexing transmission system

A highly spectral-efficient transmission system based on optical code-division multiplexing (OCDM) technique is investigated. To meet the rapid increase in the demand of data bandwidth, spectral efficiency is becoming a key factor in optical transport systems. Several modulation formats along with the optical receiver design have been proposed to upgrade the spectral efficiency. OCDM is one of the promising techniques for this purpose. OCDM is the other class of multiplexing technique than optical time-division multiplexing and wavelength-division multiplexing (WDM). OCDM provides unique features such as asynchronous transmission, secure communication, soft capacity on demand, and high degree of scalability. In this paper, we apply OCDM technique to the highly spectral-efficient transmission system by quaternary phase-shift keying optical encoding/decoding along with ultrafast optical time-gating and optical hard thresholding. As a result, a transmission of 6.4 Tbit/s OCDM/WDM (4 OCDM/spl times/40 WDM/spl times/40 Gbit/s) using only C-band wavelength region is experimentally demonstrated with 1.6-bit/s/Hz spectral efficiency.     

基于Optisystem的光电色散补偿技术的性能分析

为了实现光信号的有效传输,减少光纤中色散和非线性效应对通信系统的影响,提出一种基于光纤布拉格光栅(fiber bragg grating,FBG)中间补偿的光电色散补偿技术,即在传输链路上采用FBG中间补偿方式,在接收端采用电色散补偿技术,分别实现了对40 Gbit/s,归零(RZ)码信号的单信道和多信道系统的色散补偿.通过与全光色散补偿技术作对比,可以得到在入射功率较高的条件下,光电色散补偿技术的补偿性能明显优于全光色散补偿技术,同时能够保持较高的Q值,为系统以后的升级、扩容做铺垫.     

Experimental studies of optical Raman amplifiers for 1.3‐µm wavelength band and its application to 20 Gbit/s × 2 WDM transmission

Configurations of a Raman amplifier suitable for a 1.3‐µm wavelength band are discussed and their properties are experimentally investigated. Pump light with a wavelength of 1.23 µm that is necessary for the Raman amplification in the 1.3‐µm wavelength band is obtained using a 1.06‐µm fiber laser and Raman laser technique. Concerning the Raman laser, wavelength conversion from 1.06 µm to 1.23 µm is effectively achieved using a cavity configuration including fiber Bragg gratings and a dispersion‐shifted fiber. On the other hand, a conventional dispersion compensation fiber which has an essential property of high nonlinearity is applied in order to obtain large gain at 1.3 µm. Net gain of 35 dB and output power of 15 dBm are achieved. To confirm the applicability of the Raman amplifiers to high‐speed optical transmissions, experiments of 20 Gbit/s × 2 WDM repeaterless transmission through a 80‐km conventional single‐mode fiber are carried out. The 1.3‐µm signal should be degraded due to the dispersion caused by the dispersion compensation fiber in the Raman amplifier; However, bit error rate of less than 10 to 12 is obtained at both wavelengths, which is sufficient performance for practical uses. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(1): 58–65, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10137     

Design of amplifier- and modulator-integrated laser diode for 10-Gb/s 80-km transmission

We present the amplifier- and modulator-integrated laser diode designed for 10-Gb/s transmission over 80-km distance. An antireflection window structure is implemented at the tilt facet of the amplifier to reduce optical feedback by 40 dB. A monitor photodiode is monolithically integrated in the antireflection window region for accurate power regulation. To better control the amplifier input power and to reduce the feedback of amplified spontaneous emission, an attenuation inner-window is incorporated by removing a section of the waveguide. The reproducibility of the chip fabrication process is tested to confirm the design margin. Through amplifying the modulated signals and reducing modulator chirp by amplifier saturation, high-power optical transmission is demonstrated.